.input-num {
    height: 100px;
    width: 300px;
    user-select: none;
}

.input-num::after {
    content: '';
    display: block;
    clear: both;
}

.input-num button {
    height: 100px;
    width: 100px;
    background-color: #eee;
    border: none;
    outline: none;
    float: left;
}

.input-num button:hover {
    background-color: #f40;
    transition: background 1s;
}

.input-num button:nth-child(1) {
    border-top-left-radius: 10px;
    border-bottom-left-radius: 10px;
}

.input-num button:nth-child(3) {
    border-top-right-radius: 10px;
    border-bottom-right-radius: 10px;
}

.input-num span {
    height: 100px;
    width: 100px;
    text-align: center;
    line-height: 100px;
    background-color: #eee;
    float: left;
}